% C3_3.m
% Computer example C3.3
% The signal g(t) in Fig.3.49a is passed through an ideal low-pass filter
% of transfer function H(f), shown in Fig.3.49b. Usig DFT, find the filter
% output
% C3_2.m is imported to get Gq.

clear all; close all; 
clc;
C3_2;% import C3_2.m
q=0:31;q=q';
for m=1:length(q)% generate Hq
    if q(m)>=0 && q(m)<=7
        Hq(m)=1;
    end
    if q(m)>=25 && q(m)<=31
        Hq(m)=1;
    end
    if q(m)>=9 && q(m)<=23
        Hq(m)=0;
    end
    if q(m)==8 || q(m)==24
        Hq(m)=0.5;
    end   
end
Hq=Hq';
Yq=Gq.*Hq;
yk=ifft(Yq);% compute yk
clf,stem(q,yk);% plot yk